1. Field of the Invention
The present invention relates to technology for processing document data including meta-information, and printing control data having reference information to the meta-information and conditional print settings that depend on the contents of the meta-information.
2. Description of the Related Art
A printing method known as variable data printing (VDP) is in use. With VDP, data is divided into fixed portions and variable portions, and the data of the variable portions is supplied from a data source such as a relational database (RDB) or a comma-separated values (CSV) file. Here, different contents are printed per record, by associating digits (or fields) of the data source with variable portions of a template document, and applying the digits per line (or record) of the data source.
With VDP, it is possible to create direct mail or the like in which product information provided is changed in accordance with customer information, for example. Also, a collection of logical information such as page layout, data source and the like required in VDP is called a VDP document. In recent years, there have emerged formats in which information on recipients (e.g.: IDs for identifying recipients, gender, addresses, etc.) is embedded in VDP documents as metadata.
Generally, job definition format (JDF) is used as the method for controlling the print settings for when printing a VDP document. The JDF specification includes a JDF JobTicket as a data format for conveying the printing control method to a device. In recent years, a method has been used in which printing is performed after configuring print settings variably for every recipient of printed matter, using metadata embedded in a VDP document and a JDF JobTicket that refers to the metadata. For example, in the case where metadata that uses an attribute of the recipient such as “gender”, for example, as a key is included in the VDP document, it is possible to configure conditional settings in the JDF JobTicket, such that matte paper is set if the value of the “gender” key is “male”, and gloss paper is set if the value of the “gender” key is “female”.
Thus, while diverse print settings can be configured by embedding metadata in a VDP document, there is also a risk of personal information included in the VDP document being disclosed should the metadata be viewed by a third party. For example, in the case where the printing process is outsourced, it is conceivable that the VDP document will be leaked from the outsourcee to a third party, and that embedded metadata (e.g., personal information of the recipient of printed matter) will be viewed.
As technology for preventing such disclosure of the contents of a print job, technology for encrypting the entire print job has heretofore been disclosed. Japanese Patent Laid-Open No. 2006-294017 proposes a technique in which the document to be printed is encrypted by the host of the printer and converted to printer-independent intermediate data, and the intermediate data is decrypted and printed by the printer.
There is also literature that discloses technology for performing obfuscation processing on specific confidential character strings in the case where the document text contains confidential information, and decrypting the confidential character strings in the printer. For example, Japanese Patent Laid-Open No. 2009-251803 proposes a technique for obfuscating confidential information included in an XML paper specification (XPS) document. In Japanese Patent Laid-Open No. 2009-251803, designation of a character string as confidential information is received from a user, the character string is replaced with globally unique identifier (GUID), and the GUID and the original character string are written as a pair into XPS metadata. In the case where the XPS document is read by an XPS viewer, the confidential information is displayed in the state of having been replaced with the GUID, since the metadata portion is skipped. The obfuscated XPS document is then restored in the printer.
If encryption is performed as described in Japanese Patent Laid-Open No. 2006-294017, it will be possible to prevent disclosure of information, at least while the information is encrypted. However, in order to implement variable print settings on an encrypted document, the metadata needs to be decrypted at some stage during the printing process. There is a chance that personal information will be viewed at some point after decryption, such as when a decrypted job is placed in a spool folder, for example.
Also, a special apparatus for performing decryption has to be provided. For example, if decryption is performed in the printer, a special function for performing decryption has to be added to the printer. Furthermore, there is a disadvantage in that the processing is time-consuming depending on the decryption processing, and printing performance decreases. Also, in the case of encrypting a document, there is a risk of the code being deciphered depending on the encryption algorithm.
Also, in the case of Japanese Patent Laid-Open No. 2009-251803, since confidential information is written in plain text in the metadata portion included in the document, there is a possibility of confidential information being disclosed when the contents of the document are analyzed.